1. Field of the Invention
The present invention relates to an element for a heat accumulator that utilizes off-peak power to store heat that will be used, for example, for cooling and heating during the daytime.
2. Description of the Prior Art
It is quite important to create a demand for off-peak power to improve utilization of power generation facilities and to level the load of power generation facilities during the day.
As a method of using off-peak power during the daytime, a method of accumulating heat in a heat accumulator at a high-temperature is known. Such a heat accumulator uses a magnesite brick whose major component is magnesia, or a brick whose major component is iron oxide. In an apparatus using the brick as a heat-accumulating source, a heat-accumulating type heater can be mentioned. Such heat-accumulating type heaters are remarkably popular, particularly, for example, in West Germany, but in Japan they are used only in primary schools, homes for the aged, and hospitals.
However, while the brick used in such conventional heat accumulators can advantageously accumulate heat up to about 600.degree. C., which is a high heat accumulating capacity and about 6 times that of water per unit of volume, such a brick has the defect that the weight per unit of heat capacity is high, because the specific gravity thereof is as high as 3.0 to 5.0. Therefore, the total weight of the above-discussed heat-accumulating type heater using a heat accumulator employing a conventional brick is large (for example, the weight of one commercially available is about 200 kg). Accordingly, it is unsatisfactory for use in the home, for example, in view of problems in installation and mobility.